1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
require 'active_support/core_ext/hash/keys'
require "set"
module ActiveRecord
class Relation
class HashMerger # :nodoc:
attr_reader :relation, :hash
def initialize(relation, hash)
hash.assert_valid_keys(*Relation::VALUE_METHODS)
@relation = relation
@hash = hash
end
def merge #:nodoc:
Merger.new(relation, other).merge
end
# Applying values to a relation has some side effects. E.g.
# interpolation might take place for where values. So we should
# build a relation to merge in rather than directly merging
# the values.
def other
other = Relation.create(relation.klass, relation.table)
hash.each { |k, v|
if k == :joins
if Hash === v
other.joins!(v)
else
other.joins!(*v)
end
elsif k == :select
other._select!(v)
else
other.send("#{k}!", v)
end
}
other
end
end
class Merger # :nodoc:
attr_reader :relation, :values, :other
def initialize(relation, other)
@relation = relation
@values = other.values
@other = other
end
NORMAL_VALUES = Relation::SINGLE_VALUE_METHODS +
Relation::MULTI_VALUE_METHODS -
[:joins, :where, :order, :bind, :reverse_order, :lock, :create_with, :reordering, :from] # :nodoc:
def normal_values
NORMAL_VALUES
end
def merge
normal_values.each do |name|
value = values[name]
# The unless clause is here mostly for performance reasons (since the `send` call might be moderately
# expensive), most of the time the value is going to be `nil` or `.blank?`, the only catch is that
# `false.blank?` returns `true`, so there needs to be an extra check so that explicit `false` values
# don't fall through the cracks.
unless value.nil? || (value.blank? && false != value)
if name == :select
relation._select!(*value)
else
relation.send("#{name}!", *value)
end
end
end
merge_multi_values
merge_single_values
merge_joins
relation
end
private
def merge_joins
return if values[:joins].blank?
if other.klass == relation.klass
relation.joins!(*values[:joins])
else
joins_dependency, rest = values[:joins].partition do |join|
case join
when Hash, Symbol, Array
true
else
false
end
end
join_dependency = ActiveRecord::Associations::JoinDependency.new(other.klass,
joins_dependency,
[])
relation.joins! rest
@relation = relation.joins join_dependency
end
end
def merge_multi_values
lhs_wheres = relation.where_values
rhs_wheres = values[:where] || []
lhs_binds = relation.bind_values
rhs_binds = values[:bind] || []
removed, kept = partition_overwrites(lhs_wheres, rhs_wheres)
where_values = kept + rhs_wheres
bind_values = filter_binds(lhs_binds, removed) + rhs_binds
conn = relation.klass.connection
bv_index = 0
where_values.map! do |node|
if Arel::Nodes::Equality === node && Arel::Nodes::BindParam === node.right
substitute = conn.substitute_at(bind_values[bv_index].first, bv_index)
bv_index += 1
Arel::Nodes::Equality.new(node.left, substitute)
else
node
end
end
relation.where_values = where_values
relation.bind_values = bind_values
if values[:reordering]
# override any order specified in the original relation
relation.reorder! values[:order]
elsif values[:order]
# merge in order_values from relation
relation.order! values[:order]
end
relation.extend(*values[:extending]) unless values[:extending].blank?
end
def merge_single_values
relation.from_value = values[:from] unless relation.from_value
relation.lock_value = values[:lock] unless relation.lock_value
unless values[:create_with].blank?
relation.create_with_value = (relation.create_with_value || {}).merge(values[:create_with])
end
end
def filter_binds(lhs_binds, removed_wheres)
return lhs_binds if removed_wheres.empty?
set = Set.new removed_wheres.map { |x| x.left.name.to_s }
lhs_binds.dup.delete_if { |col,_| set.include? col.name }
end
# Remove equalities from the existing relation with a LHS which is
# present in the relation being merged in.
# returns [things_to_remove, things_to_keep]
def partition_overwrites(lhs_wheres, rhs_wheres)
if lhs_wheres.empty? || rhs_wheres.empty?
return [[], lhs_wheres]
end
nodes = rhs_wheres.find_all do |w|
w.respond_to?(:operator) && w.operator == :==
end
seen = Set.new(nodes) { |node| node.left }
lhs_wheres.partition do |w|
w.respond_to?(:operator) && w.operator == :== && seen.include?(w.left)
end
end
end
end
end
|
